U.S. patent application number 15/591391 was filed with the patent office on 2018-01-25 for reflective display apparatus.
This patent application is currently assigned to Alpine Electronics, Inc.. The applicant listed for this patent is Alpine Electronics, Inc.. Invention is credited to Takashi Yasumoto.
Application Number | 20180024409 15/591391 |
Document ID | / |
Family ID | 60988437 |
Filed Date | 2018-01-25 |
United States Patent
Application |
20180024409 |
Kind Code |
A1 |
Yasumoto; Takashi |
January 25, 2018 |
REFLECTIVE DISPLAY APPARATUS
Abstract
A reflective display apparatus includes an image display panel
including a liquid crystal panel and a backlight unit, a half
mirror, and an electrochromic panel arranged in a layered manner.
When the image display panel stops operating and power supply to
the electrochromic panel is stopped, the half mirror reflects light
coming from the rear of a vehicle and the reflected light is
directed rearward. The reflected light enables a driver to check a
situation behind the vehicle under such conditions.
Inventors: |
Yasumoto; Takashi;
(Iwaki-city Fukushima, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Alpine Electronics, Inc. |
Tokyo |
|
JP |
|
|
Assignee: |
Alpine Electronics, Inc.
|
Family ID: |
60988437 |
Appl. No.: |
15/591391 |
Filed: |
May 10, 2017 |
Current U.S.
Class: |
348/148 |
Current CPC
Class: |
G06K 9/00791 20130101;
G02F 2201/44 20130101; G02F 1/157 20130101; G02F 1/13318 20130101;
B60R 1/00 20130101; B60R 2001/1253 20130101; G02B 2027/0194
20130101; G02F 1/1506 20130101; G02F 2001/13312 20130101; B60R 1/12
20130101; B60R 2300/20 20130101; B60K 2370/331 20190501; G02F
2203/02 20130101; B60R 1/088 20130101; G02B 2027/0141 20130101;
B60R 1/04 20130101; B60R 2300/8066 20130101; B60K 2370/21 20190501;
G02B 2027/0138 20130101; G02B 27/0101 20130101; B60K 35/00
20130101; G02F 1/163 20130101; G02F 2201/58 20130101; B60K 2370/52
20190501 |
International
Class: |
G02F 1/163 20060101
G02F001/163; G02F 1/157 20060101 G02F001/157; B60K 35/00 20060101
B60K035/00; G02B 27/01 20060101 G02B027/01; G06K 9/00 20060101
G06K009/00; B60R 1/00 20060101 B60R001/00; G02F 1/15 20060101
G02F001/15; G02F 1/133 20060101 G02F001/133 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 25, 2016 |
JP |
2016-145658 |
Claims
1. A reflective display apparatus comprising: an image display
panel; an electrochromic panel disposed adjacent to a display side
of the image display panel; and a half mirror disposed between the
image display panel and the electrochromic panel.
2. The apparatus according to claim 1, wherein the electrochromic
panel includes two opposed transparent substrates, a transparent
electrode disposed on an inner surface of each of the transparent
substrates, and an electrolyte layer interposed between the opposed
transparent electrodes, the electrolyte layer containing a metal
ion, and wherein the metal ion is deposited on one of the
transparent electrodes in response to application of voltage across
the transparent electrodes, so that the electrochromic panel
becomes a reflective panel.
3. The apparatus according to claim 1, wherein the half mirror has
a reflectance of 10% to 40%.
4. The apparatus according to claim 1, further comprising: a camera
that captures an image of an area behind a vehicle, wherein the
image display panel is capable of displaying the captured image of
the area behind the vehicle.
5. The apparatus according to claim 1, further comprising: a
controller that controls the image display panel and the
electrochromic panel; and a photodetector that senses external
light, wherein when the photodetector senses a light intensity
below a predetermined value, the controller performs first control
to drive the image display panel without applying voltage across
the electrodes of the electrochromic panel, and wherein when the
photodetector senses a light intensity at or above the
predetermined value, the controller performs second control to
apply the voltage across the electrodes of the electrochromic panel
without driving the image display panel.
6. The apparatus according to claim 5, wherein when application of
the voltage across the electrodes of the electrochromic panel is
stopped during the second control, the controller continues a state
in which the image display panel is not driven.
Description
RELATED APPLICATION
[0001] The present application claims priority to Japanese Patent
Application Number 2016-145658, filed Jul. 25, 2016, the entirety
of which is hereby incorporated by reference.
BACKGROUND
1. Field
[0002] The present disclosure relates to a reflective display
apparatus that includes an image display panel for displaying, for
example, a captured image of an area behind a vehicle and that has
a reflecting function.
2. Description of the Related Art
[0003] Japanese Unexamined Patent Application Publication No.
2005-231605 and Japanese Unexamined Patent Application Publication
(Translation of PCT Application) No. 2009-529452 disclose
reflective display apparatuses for viewing an image of an area
behind a vehicle.
[0004] A rearward checking apparatus disclosed in Japanese
Unexamined Patent Application Publication No. 2005-231605 is a
side-view mirror including a half mirror and a liquid crystal
display disposed at the rear of the half mirror. A vehicle is
provided with a rearward-looking camera for capturing an image of
an area behind the vehicle. The liquid crystal display displays an
image captured by the rearward-looking camera. Since the image
displayed by the liquid crystal display passes through the half
mirror, the displayed image and an image reflected by the half
mirror are combined into an image.
[0005] The rearward checking apparatus disclosed in Japanese
Unexamined Patent Application Publication No. 2005-231605 enables a
driver to visually check a situation hidden by part of a vehicle
body in a manner similar to that using a typical side-view
mirror.
[0006] A rearview assembly disclosed in Japanese Unexamined Patent
Application Publication (Translation of PCT Application) No.
2009-529452 includes a mirror element and a video display disposed
at the rear of the mirror element. As described in Japanese
Unexamined Patent Application Publication (Translation of PCT
Application) No. 2009-529452, exemplary combinations of the video
display and the mirror element include a combination of a liquid
crystal display and an electrochromic mirror element.
[0007] The rearview assembly disclosed in Japanese Unexamined
Patent Application Publication (Translation of PCT Application) No.
2009-529452 is configured as follows. Under high ambient light
conditions, the electrochromic mirror element is operated so that a
reflected image is visible. Under low ambient light conditions, the
electrochromic mirror element is stopped and the liquid crystal
display is operated instead of the electrochromic mirror element so
that an image displayed by the liquid crystal display is
visible.
[0008] The rearward checking apparatus disclosed in Japanese
Unexamined Patent Application Publication No. 2005-231605 provides
a combined image of the image displayed by the liquid crystal
display and the image reflected by the half mirror. Under high
ambient light conditions outside the vehicle, the image displayed
by the liquid crystal display is not clearly visible and the image
reflected by the half mirror is not clearly provided, so that it is
difficult for the driver to reliably visually check a situation
behind the vehicle. Since the rearward checking apparatus, serving
as a side-view mirror, is disposed on the exterior of the vehicle,
it is particularly difficult to display a clear combined image.
[0009] The rearview assembly disclosed in Japanese Unexamined
Patent Application Publication (Translation of PCT Application) No.
2009-529452 can provide a relatively clear reflected image of a
situation behind the vehicle under high ambient light conditions by
using the electrochromic mirror element. To continue a reflecting
operation of the electrochromic mirror element, however, voltage
has to be continuously applied across electrodes.
[0010] If the engine is turned off and the application of voltage
across the electrodes is accordingly stopped, the electrochromic
mirror element does not function as a mirror element. Furthermore,
if power supply is stopped, the liquid crystal display is also
stopped, so that there is no means for helping a driver to check a
situation behind the vehicle. The same problem occurs during an
idle reduction mode during which the engine is stopped while the
vehicle is temporarily stopped during travel. During the idle
reduction mode, the driver cannot check a situation behind the
vehicle, leading to reduced safety of the vehicle during travel. In
addition, continuous power supply to the electrochromic mirror
element or the liquid crystal display during the idle reduction
mode results in an excessive power consumption.
[0011] Furthermore, the electrochromic mirror element may not be
operated due to failure of the electrochromic mirror element or an
electric system. In such an emergency, the driver cannot view a
reflected image of a situation behind the vehicle. If such an
emergency occurs under high ambient light conditions, such as
daytime, in which it is hard to see an image displayed by the
liquid crystal display, it is very dangerous.
SUMMARY
[0012] The present disclosure has been made to solve the
above-described problems in the art. The present disclosure
provides a reflective display apparatus capable of providing a
reflected image of a situation, for example, behind a vehicle, if
power supply to an electrochromic panel is shut off or if the
electrochromic panel fails.
[0013] According to an aspect of the present disclosure, a
reflective display apparatus includes an image display panel, an
electrochromic panel disposed adjacent to a display side of the
image display panel, and a half mirror disposed between the image
display panel and the electrochromic panel.
[0014] In this aspect, preferably, the electrochromic panel
includes two opposed transparent substrates, a transparent
electrode disposed on an inner surface of each of the transparent
substrates, and an electrolyte layer interposed between the opposed
transparent electrodes. The electrolyte layer contains a metal ion.
The metal ion is deposited on one of the transparent electrodes in
response to application of voltage across the transparent
electrodes, so that the electrochromic panel becomes a reflective
panel.
[0015] In this aspect, the half mirror may have a reflectance of
10% to 40%.
[0016] The apparatus according to this aspect may further include a
camera that captures an image of an area behind a vehicle. The
captured image of the area behind the vehicle can be displayed by
the image display panel.
[0017] The apparatus according to this aspect may further include a
controller that controls the image display panel and the
electrochromic panel and a photodetector that senses external
light. When the photodetector senses a light intensity below a
predetermined value, the controller may perform a first control to
drive the image display panel without applying voltage across the
electrodes of the electrochromic panel. When the photodetector
senses a light intensity at or above the predetermined value, the
controller may perform a second control to apply the voltage across
the electrodes of the electrochromic panel without driving the
image display panel.
[0018] In this aspect, preferably, when application of the voltage
across the electrodes of the electrochromic panel is stopped during
the second control, the controller continues a state in which the
image display panel is not driven.
[0019] In the reflective display apparatus according to this aspect
of the present disclosure, while voltage is applied across the
electrodes of the electrochromic panel, the electrochromic panel
functions as a reflective panel. When the voltage application to
the electrodes of the electrochromic panel is stopped, the
electrochromic panel becomes a light transmissive panel. The image
display panel is operated so that an image displayed by the image
display panel is visible.
[0020] When the voltage application to the electrodes of the
electrochromic panel is stopped while the electrochromic panel has
to function as a reflective panel, the image display panel is kept
stopped and a display screen of the image display panel is in black
or a dark color so that an image reflected by the half mirror is
visible. Consequently, a reflected image can be viewed at all times
during stopping of the engine of the vehicle, during the idle
reduction mode, or if the electrochromic panel has an abnormality
in operation.
[0021] In addition, since the half mirror has a low reflectance of
10% to 40%, an image displayed by the image display panel is
clearly visible while the image display panel is in operation.
While a display operation of the image display panel is stopped,
the half mirror can provide reflected light having a predetermined
intensity.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a diagram explaining a reflective display
apparatus according to an embodiment of the present disclosure and
illustrates the apparatus used as a rear-view mirror of a
vehicle;
[0023] FIG. 2 is a cross-sectional view illustrating an exemplary
configuration of the reflective display apparatus according to an
embodiment of the present disclosure;
[0024] FIG. 3 is a cross-sectional view of an electrochromic panel
included in the reflective display apparatus according to an
embodiment of the present disclosure; and
[0025] FIG. 4 is a circuit block diagram of the reflective display
apparatus according to an embodiment of the present disclosure.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Configuration of Reflective Display Apparatus 10
[0026] FIG. 1 illustrates a reflective display apparatus 10
according to an embodiment of the present disclosure. FIG. 1
illustrates a steering wheel 1, a shift lever 2, and a windshield 3
when viewed from a vehicle interior of an automobile. In the
present embodiment, the reflective display apparatus 10 is used as
a rear-view mirror of the automobile and is disposed adjacent to an
upper end of the windshield 3.
[0027] The reflective display apparatus 10 according to the present
disclosure is not limited to the rear-view mirror. The reflective
display apparatus 10 can be used as a door mirror (side-view
mirror). Furthermore, the reflective display apparatus 10 can be
used to reflect or display an image of a scene to the rear of a
vehicle other than the automobile, for example, a train or a
two-wheeler.
[0028] FIG. 2 is a cross-sectional view of an exemplary
configuration of the reflective display apparatus 10. In FIG. 2, a
casing that accommodates components of the reflective display
apparatus 10 is not illustrated. Although the components of the
reflective display apparatus 10 are illustrated with gaps between
adjacent components in FIG. 2, it is preferred that the components
accommodated in the casing be arranged with gaps as small as
possible or be in contact without gaps.
[0029] In FIG. 2, the Y1 direction is a direction in which the
reflective display apparatus 10 faces the vehicle interior, that
is, a rearward direction toward the rear of the vehicle, or
reflection direction. The Y2 direction is a forward direction
toward the front of the vehicle, or the direction of travel of the
vehicle and is opposite to the reflection direction.
[0030] The reflective display apparatus 10 includes an image
display panel 11 located farthest in the Y2 direction opposite to
the reflection direction. The image display panel 11 includes a
liquid crystal panel 12, a front polarizer 13a located farther in
the Y1 direction than the liquid crystal panel 12, a rear polarizer
13b located farther in the Y2 direction than the liquid crystal
panel 12, and a backlight unit 14 located farther in the Y2
direction than the rear polarizer 13b. The liquid crystal panel 12
is a transmissive panel capable of providing color display. Display
light V emitted from the backlight unit 14 passes through the
liquid crystal panel 12 and travels in the Y1 direction.
[0031] The image display panel 11 may be any self-light-emitting
display panel, such as an electroluminescent display panel or a
plasma display panel.
[0032] Furthermore, a half mirror 15 and an electrochromic panel 20
are arranged in that order in the Y1 direction in front of the
image display panel 11. In addition, a front panel 16 is disposed
on the surface of the electrochromic panel 20 facing in the Y1
direction.
[0033] The half mirror 15 has a reflectance less than 50%, or a
reflectance of 10% to 40%, preferably 10% to approximately 30%. In
the present embodiment, the reflectance is 20%. The front panel 16
is a transparent panel. In some embodiments, a translucent touch
sensor capable of detecting a change in capacitance to determine
the position of an approaching finger may further be disposed on
the surface of the front panel 16 facing in the Y2 direction.
[0034] FIG. 3 is a cross-sectional view of an exemplary
configuration of the electrochromic panel 20. The electrochromic
panel 20 includes a transparent substrate 21 facing in the Y1
direction and a transparent substrate 22 facing in the Y2 direction
such that the transparent substrates 21 and 22 are opposed parallel
to each other. The transparent substrates 21 and 22 are, for
example, glass substrates. The transparent substrate 21 has a
transparent electrode 23 on an inner surface of the substrate. The
transparent substrate 22 has a transparent electrode 24 on an inner
surface of the substrate. Each of the transparent electrodes 23 and
24 is formed of, for example, an indium tin oxide (ITO) layer.
[0035] An electrolyte layer 25 is interposed between the
transparent electrodes 23 and 24. The electrolyte layer 25 contains
a metal ion. In the present embodiment illustrated in FIG. 3, the
metal ion is a silver cation 26. In some embodiments, any of the
transparent electrodes 23 and 24 may be an ion supply electrode for
providing (precipitating) a metal ion upon voltage application.
[0036] Referring to FIGS. 3 and 4, the electrochromic panel 20 is
connected to a switching circuit 28. The switching circuit 28
includes a direct current power supply 28a and a switch element 28b
capable of simultaneously switching the transparent electrodes 23
and 24 between connection to the direct current power supply 28a
and disconnection therefrom. When the switch element 28b is turned
on and voltage is applied across the transparent electrodes 23 and
24, reduction occurs at the transparent electrode 23, serving as a
cathode, and oxidation occurs at the transparent electrode 24,
serving as an anode. Consequently, the silver cations 26 are
deposited on the transparent electrode 23, so that the
electrochromic panel 20 functions as a reflective panel.
[0037] When the voltage application to the transparent electrodes
23 and 24 is stopped and there is no difference in potential
between the transparent electrodes 23 and 24, reduction and
oxidation do not occur, so that the electrochromic panel 20 becomes
a light transmissive panel.
[0038] FIG. 4 is a block diagram of the reflective display
apparatus 10 according to the present embodiment of the present
disclosure. The reflective display apparatus 10 includes a
controller 30. The controller 30 includes, as major components, a
central processing unit (CPU) and a memory. The controller 30
provides a switching signal S1 to the switching circuit 28. In
addition, an information signal S2 concerning an operation state of
the electrochromic panel 20 is fed back to the controller 30.
[0039] The reflective display apparatus 10 includes a video camera
31 for capturing an image of a scene behind the vehicle. A signal
obtained by an imaging element, such as a charge-coupled device
(CCD), included in the video camera 31 is sent to an imaging
circuit 32. A video signal S3 generated by the imaging circuit 32
is provided to the controller 30. The image display panel 11 is
driven by a liquid crystal drive circuit 17. The controller 30
provides a display signal S4 to the liquid crystal drive circuit
17. The display signal S4 includes the video signal S3 generated by
the imaging circuit 32.
[0040] A photodetector 33 is disposed at any position in the
vehicle interior or a vehicle exterior. A light intensity signal S5
obtained by the photodetector 33 is provided to the controller
30.
[0041] An operation of the reflective display apparatus 10 will now
be described below.
Display Operation of Image Display Panel 11
[0042] The photodetector 33 in FIG. 4 senses the intensity of
ambient light and provides the light intensity signal S5 to the
controller 30 at all times. When the controller 30 determines that
an intensity indicated by the light intensity signal S5 is less
than or equal to a predetermined value or less than the
predetermined value, that is, the ambient light has an intensity at
or below the predetermined value, the controller 30 provides the
switching signal S1 to the switching circuit 28, thus turning off
the switch element 28b of the switching circuit 28 in FIG. 3. This
stops the voltage application to the transparent electrodes 23 and
24 of the electrochromic panel 20.
[0043] Consequently, the silver cations 26 are not deposited on the
transparent electrode 23, so that the electrochromic panel 20
becomes a light transmissive panel.
[0044] Furthermore, the controller 30 provides the display signal
S4 to the liquid crystal drive circuit 17. In response to the
display signal S4, the liquid crystal drive circuit 17 is activated
to drive the image display panel 11, so that an image of a scene
behind the vehicle (in the Y1 direction) captured by the video
camera 31 is displayed on the liquid crystal panel 12.
Simultaneously, the backlight unit 14 is lit on. As illustrated in
FIG. 2, the display light V of the image displayed by the image
display panel 11 passes through the half mirror 15, the
electrochromic panel 20, and the front panel 16, so that the image
of the scene behind the vehicle captured by the video camera 31 is
displayed on the reflective display apparatus 10 in FIG. 1
Reflective Display by Electrochromic Panel 2
[0045] When the controller 30 determines that an intensity
indicated by the light intensity signal S5 is greater than the
predetermined value or greater than or equal to the predetermined
value, that is, the ambient light has an intensity at or above the
predetermined value, the controller 30 provides the switching
signal S1 to the switching circuit 28, thus turning on the switch
element 28b of the switching circuit 28 in FIG. 3. Consequently,
the voltage is applied across the transparent electrodes 23 and 24
of the electrochromic panel 20.
[0046] As a result, the silver cations 26 are deposited on the
transparent electrode 23, so that the electrochromic panel 20
functions as a reflective panel.
[0047] Furthermore, the display signal S4 is not provided to the
liquid crystal drive circuit 17 by the controller 30 and the liquid
crystal drive circuit 17 accordingly enters a stop mode, thus
stopping the display operation of the image display panel 11.
Consequently, as illustrated in FIG. 2, the electrochromic panel 20
reflects light coming from the rear of the vehicle, so that
reflected light R1 is directed in the Y1 direction. At this time,
the electrochromic panel 20 reflects the light at a much higher
reflectance than the half mirror 15.
[0048] In this case, the reflective display apparatus 10 in FIG. 1
functions as a reflector. With the reflective display apparatus 10,
a driver can check a situation behind the vehicle by perceiving the
reflected light R1 in a manner similar to that using a typical
rear-view mirror.
When Voltage Application to Electrochromic Panel 20 is Stopped
[0049] As described above, while the controller 30 determines that
an intensity indicated by the light intensity signal S5 is greater
than the predetermined value or greater than or equal to the
predetermined value and the display operation of the image display
panel 11 is stopped, the voltage is applied across the transparent
electrodes 23 and 24 of the electrochromic panel 20 and the
reflective display apparatus 10 is used as a reflector under normal
conditions.
[0050] In the reflective display apparatus 10 installed in the
vehicle, however, the voltage application to the transparent
electrodes 23 and 24 of the electrochromic panel 20 may be stopped
during the above-described operation, for example, when the engine
is stopped while the vehicle is stopped, when power supply to the
transparent electrodes 23 and 24 is stopped in the idle reduction
mode, or when power supply to the transparent electrodes 23 and 24
is stopped due to failure of the electrochromic panel 20 or an
electric system.
[0051] In this case, the electrochromic panel 20 becomes a light
transmissive panel. Since the half mirror 15 is located farther in
the Y2 direction than the electrochromic panel 20, light coming
from the rear of the vehicle passes through the front panel 16 and
the electrochromic panel 20 and is partly reflected by the half
mirror 15 as illustrated in FIG. 2. Reflected light R2 is directed
in the Y1 direction.
[0052] The half mirror 15 has a reflectance of 10% to 40%,
preferably 10% to approximately 30%. While the image display panel
11 is stopped, a display screen of the liquid crystal panel 12 is
in black or dark color. The reflected light R2 from the half mirror
15 accordingly enables the driver to adequately visually check a
scene behind the vehicle when looking the reflective display
apparatus 10 in FIG. 1.
[0053] While the engine is in an OFF state during stopping of the
vehicle such that the voltage application to the transparent
electrodes 23 and 24 is stopped, the driver can perceive the
reflected light R2 from the reflective display apparatus 10 to
confirm safety behind the vehicle before starting the engine.
[0054] Furthermore, if the voltage application to the transparent
electrodes 23 and 24 of the electrochromic panel 20 is stopped
during the idle reduction mode, the driver can confirm safety
behind the vehicle. It is therefore unnecessary to supply power to
the transparent electrodes 23 and 24 during the idle reduction
mode, thus reducing the power consumption.
[0055] Additionally, if the electrochromic panel 20 fails and
becomes a light transmissive panel due to failure of the
electrochromic panel 20 or trouble in a current-carrying path to
the electrochromic panel 20 while the electrochromic panel 20 is
used as a reflector, the reflected light R2 enables the driver to
check a situation behind the vehicle, thus ensuring the safety of
driving.
[0056] As illustrated in the block diagram of FIG. 4, the
information signal S2 indicating information about an operation of
the electrochromic panel 20 is provided to the controller 30 at all
times. When the controller 30 determines based on the information
signal S2 that power is not supplied to the transparent electrodes
23 and 24, the controller 30 performs control to continue a state
in which the image display panel 11 does not perform the display
operation, regardless of a value indicated by the light intensity
signal S5 from the photodetector 33. Consequently, the reflected
light R2 from the half mirror 15 enables the driver to confirm
safety behind the vehicle regardless of whether the intensity of
external light sensed by the photodetector 33 is high or low.
[0057] In the reflective display apparatus 10 according to the
present embodiment, since the half mirror 15 has a reflectance of
10% to 40%, preferably 10% to approximately 30%, there is no
deterioration in display light V passing through the half mirror 15
during operation of the image display panel 11. In addition, while
the operation of the image display panel 11 is stopped, the
reflected light R2 having an intensity that enables the driver to
check a situation behind the vehicle can be directed in the Y1
direction.
* * * * *